Crankshaft grinder



Jan. 26, 1943 J. SUNNEN CRANK SHAFT GRINDER Original Filed May 22, 1959 6 Sheets-Sheet l INVENTOR JOSEPH SUNNEN ATTORNEY Jan. 26, 1943 .1. SUNNEN CRANK SHAFT GRINDER Original Filed May 22, 1959 6 Sheets-Sheet 2 INVENTOR JOSEPH SUNNEN ATTORNEY Jan. 26, 1943 J. SUNNEN 2,309,615

CRANK SHAFT GRINDER Original Filed May 22, 1939 6 Sheets-Sheet 3 INVENTOR JOSE-PH SUNNEN ATTORNEY 1943 J. SUNNEN 2,309,615

CRANK SHAFT GRINDER Original Filed May 22 1939 6 Sheets-Sheet 4 TNVENTOR JOSEPH SUNNEN Jan. 26, 1943 J. SUNNEN 2,309,615

CRANK SHAFT GRINDER Original Filed May 22, 1939 6 Sheets-Sheet 5 INVENTOR JOSEPH SUNNEN ATTORNEY 26, 1943 SUNNEN 2,309,615

CRANK SHAFT GRINDER Original Filed May 22, 1939 6 Sheets-Sheet 6 VINVIENTOR JOSEPH SUNNEN IQR NE 5!,

Patented Jan. 26, 1943 2,309,615 cmmxsuarr GRINDER.

Joseph Sunnen, Clayton, Mo., assignor to Cornelia Sunnen, Clayton, Mo.

Original application May 22, 1939, Serial No.

Divided and this application December 29, 1939, Serial No. 311,669

16 Claims.

This invention relates to devices for grinding cylindrical surfaces, and it is especially intended and adapted for the grinding of eccentrically mounted cylindrical surfaces such as the crank shaft bearings of an automobile. The device is constructed and arranged, however, so as to be capable of grinding the concentric main bearings as well as eccentric crank bearings.

This device is particularly intended for use byl' repair shops in regrinding worn crank shafts as distinguished from the ,original factory grinding of the crank bearings. For this reason, it is necessary to have a light, simple, and preferably portable device.

Automobile crank shafts'of the type generally in use are not provided with any convenient means for lining up a grinder to grind the cranks true to an axis which is parallel to the main axis of the crank shaft, and, for this reason, it is "as a means of attachment, and, second, if the crank shaft has been disassembled from the engine, it is mounted between centers in an engine lathe or similar device. Both of these arrangements involve the necessity of rotating the crank shaft while grinding the crank bearings, and the provision of means whereby the grinder may follow the crank in its rotation.

When the crank bearings are to be ground without removing the crank shaft from the engine, I mount the guide frame and shaft on the engine base in parallelism with the main axis of the crank shaft. A counter shaft is pivotally connected to the guide shaft so as to keep it parallel therewith while permitting it to swing in the arc of a circle about the guide shaft. I pivotally connect to the guide shaft a motor carrying arm which is provided at its free end.

with pivot means also parallel to the main axis of the crank shaft. The grinder and its driving motor are mounted on this pivot means. At the end of the motor frame, I attach a guide arm terminating in a hook which hangs on the surface of the crank which is to be ground, the weight of the motor grinder being used to maintain. the hook in engagement with the crank during its rotation. The cutting surface of the grinding wheel is adjustably mounted adjacent the cylindrical surface of the crank which is to be ground at a point opposed from the points of contact between the hook and the bearing surface.

When "the crank shaft is disassembled it is mounted between centers as in a lathe, and may be ground in substantlallythe same way as when the crank shaft is in the car, but it is necessary to provide a counterweight to overcome the weight of the grinder and hold the hook firmly against the lower partof the crank. The weight is mounted at one end ofthe walking beam which is pivoted to a frame or guide therefor. This guide shaft is mounted on the lathe by means of a frame similar to the guide shaft and frame used when grinding the crank bearings while the crank shaft is mounted'on the engine. The chief diiference is that the weight of the grinder must be overcome so that, the hook will be firmly held in contact with the crank, and this is accomplished by means of the counterweight.

.When the main bearings of the crank shaft are to .be ground, the crankshaft is essentially completely disassembled from the engine and placed between centers in a lathe or similar device, In this way, perfect alignment of the main bearings can be maintained, but in order to insure such alignment, it is desirable to locate the grinding wheel with respect to the centers in the ends of the crank shaft rather than to attempt ,thereof. By this arrangement, the rocking action of the motor with respect to the guide arm is retained, but the motor is otherwise station-' ary with respect to the center of the crank shaft. Where the crank bearings are to be ground without removing the crank shaft from the engine, it is necessary for the grinding wheel to follow the crank while it is rotated in the crankcase. The space for this operation is limited, and it is therefore necessary to provide a grinding'wheel of small size which may be projected up into the crankcase between the crank cheeks as it follows the crank bearing in its rotation.

For the reasons above indicated, I use a comparatively small grinding wheel, the diameter of which may beapproximately the same as the length of the bearing which is to be ground. The wheel is preferably of the cup type, the grinding surface being on the radial face or end of the wheel and not on its cylindrical outer surface.

Because of the grinding wheel size and structure it is, therefore, necessary not only to rotate the crank shaft and operate the grinder motor to accomplish the grinding, but it is also necessary to sweep the face of the grinder tangentially across the surface of the shaft, the axis o the grinder swinging in a plane perpendicular t: the axis of the crank. It is also necessary,

uring swinging action. to maintain the corect relfitiinship between the cutting surface of the grinder and the axis of the crank. For mstance, if the distance between the plane of the circular cutting surface and the axis of the crank is one inch when axis of the grinding wheel is in a position to intersect the axis of the crank, it must remain one inch-no more and no lesswhile the wheel is being swept across the bearing. In other words, the distance between the cutting plane of the wheel and theaxis of the bearing must remain constant while the axis of the wheel is moved in a plane perpendicular to the axis of the bearing. The means of maintaining this relationship constitutes an important this invent on.

ii gbject may be accomplished by either of the two specific forms of mechanisms which I have provided, the first of which is shown in Figures 1 to 17 inclusive. and the second bemg shown in 18 to 21 inclusive. Either of these specific forms may be used in connection with the basic mechanism shown in the other figures. Thefirst form is claimed in my copending application Serial No. 275,092, filed May 22, 1939, and matured as Patent No. 2 ,240,52' 7, May 6, 1941, of which this present application is a division.

In the first form of the invention, the grinding motor is provided with a main supporting surface or surfaces at the opposite end of the motor from the grinding wheel. This surface or these surfaces are substantially fiat. guide arm is provided with a supporting surface for contact with a support of the grinder supporting surface. The said surface on the guide arm is in the form of a segment of a cylindrical surface, and is ar.ranged concentrically with respect to the center of the crank which is being ground. By this arrangement, the rocking of the grinder on its support does not change the distance between the plane of the cutting surface of the grinding wheel and the axis of the crank. By providing screw adjustment for rocking the grinder, the face of the cup-shaped grinding wheel can be swept across the crank so as to grind an exactly cylindrical surface. It is of course necessary to prevent slipping of the grinder support with respect to the hook, and I therefore provide a projection on one of the contacting surfaces to engage a recess in the other, somewhat in the nature of a one-tooth gear to permit the rocking without permitting the sliding.

It will be understood from the above description of this first form of the invention that the maintenance of the center line of the crank is coincidence with the center line of the rocker surface of the guide arm depends on the diameter of the crank, but in order to provide for the grinding of cranks of different diameter, I provide a sliding adjustment graduated with a scale between the guide arm and the hook so that the operator may know how to set the hook to grind the shaft of a given diameter. It may also be noted that a change in the adjustment of the hook is not necessary for a mere change of a few thousandths of an inch in crank diameter,

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but that adjustments to provide for changes of or more in crank diameter may readily be made.

Another condition encountered in grinders of this type is that the changes of temperature during operation of the grinder cause expansion of the shaft of the grinding wheel. In order to prevent this expansion from interfering with the accuracy of the device and also to prevent the wheel being broken by shock when sharply brought into contact with the crank shaft, I mount the grinding wheel in a thrust bearing closely adjacent the wheel and provide a telescope connection at the other end of the shaft capable of permitting some slight inward movement of the grinding wheel. This movement is normally prevented by a compression spring which is capable of yielding under abnormal pressure supplied to the grinding wheel so as to minimize the danger of breakage as well as to allow for expansion of the shaft during operation.

In order to prevent overspeeding of the grinder when it is moved out of contact with the surface which is to be ground and also to assist in cooling the motor, I provide a fan mounted on the motor shaft. The eflfect of the fan is merely to create a draft sufilcient to cool the motor at the normal grinding speed at which the wheel is intended to be operated. However, when the speed tends to increase by reason of the wheel moving out of contact with the surface which is being ground, the resistance of the fan builds up quite rapidly and prevents excessive overspeeding of the grinding wheel and motor.

During the grinding operation, the shaft becomes more or less covered with grit from the grinding wheel which would rapidly wear away the bearing surface of the hook or bearing guide. In order to prevent this, I have provided special self-adjusting bearing blocks detachably and movably mounted on the bearing guide. These bearing blocks are mounted on a central pivot with four concave surfaces terminating in sharp corners which have the action of scraping the grit off of the hearing, so that it does not get in between the bearing guide and the hearing which is being ground. In this manner, I have substantially prolonged the life of the bearing guides.

It is an object of this invention to provide a generally new and improved device and method or grinding according to the description herein.

The foregoing is accomplished by a construction illustrated in the accompanying drawings forming a part or this specification and wherein like characters of reference designate corresponding parts throughout the several views, in which Figure 1 is a diagrammatic front elevation of a crank shaft grinding machine according to my invention with a crank shaft in position to be 8round.

ings of a crank shaft: the view is taken along the line -5 of Figure 4.

Figure 6 is a detailed sectional view taken along the line 6-6 of Figure 5.

Figure 7 is a side elevation of a crank shaft grinder of the type shown in Figure 1.

Figure 8 is a sectional view taken along the line 8-8 of Figure 7.

Figure 9 is a plan view taken along the line 3-9 of Figure 8.

Figure 10 is a sectional detailed view taken along the line ill-l0 of Figure 8. I

Figure 11 is a sectional detailed view taken along the line ll--|l of Figure 7;

Figure 12 is a sectional detailed view taken along the line l2l2 of Figure 7.

Figure 13 is a detailed view taken along the A line l3l 3 of Figure 7, the crank shaft and the grinding wheel however being omitted.

Figure 14 is a cross section taken along the line |4|4 of Figure 13.

Figure 15 is a diagrammatic illustration of the A structure shown in Figures 13 and 14.

Figure 16 is the side elevation of the device used according to my invention for grinding the crank of a crank shaft without disassembling it from the engine.

Figure 17 is a cross sectional elevation of the device shown in Figure 16.

Figure 18 is a side elevation of amodifled form of my invention.

Figure 19 is a front elevation of the modification of Figure 18.

-Figure 20 is a sectional detail on line 20 -20- 01 Figure 19, and

Figure 21 is a cross section on line 2l--2| of Figure 18.

Figure 22 is a detail view showing a modified form of bearing block, a portion of the hook 24 and crank shaft being shown,

Figure 23 is a detail view taken along the line 23-43 of Figure 22.

The reference numeral i indicates the bed of a device such as a conventional engine lathe having a head stock 2, tail stock 3, face plate 4 and centers 5. When the crank shaft 5 is removed from the engine, it may be placed between the centers of the lathe as indicated in Figure 1 and driven by a conventional lathe dog '1'. The lathe is provided with the conventional carriage 8 and cross slide 3. The carriage is movable longitudinally and transversely upon the ways it and IDA, respectively, in a manner well known to the art. So much of the structure is conventional in the well known engine lathe.

The conventional crank shaft 6 is provided with centers at its ends, whereby it may be centered up and rotated in the engine lathe. It will be noted that the main bearings II are concentric with the centers 5 while the axes of the crank bearings 12 necessarily rotate in a circle and in order to grind the crank bearings while the crank shaft is mounted upon the centers, it is necessary to have a grinder which will follow a crank in its rotation.

I mount a standard l3 upon the carriage 3 or cross side of the lathe. At the upper part of the standard a walking beam 84 is pivoted as upon a counter shaft or centers l5. At the end of the walking beam which overhangs the bed of the lathe, a guide arm I6 is connected to the beam M by means of ball bearings I1. Oil holes l8 are provided if desired. A motor frame l9 containing a high speed electric motor is mounted on and carried by the guide arm Hi. The construction for supporting the motor frame and mechanism, that is the grinder proper, upon the guide arm, comprises a pair of supporting extensions 20 integral with or rigidly flxed to the guide arm it. These supports are provided with parallel holes for receiving the plugs 2|. The outer ends of the plugs are centrally drilled as at 22 and are ground von a radius such that the supporting surface or outer ends of the plugs 2| will be concentric with the center of a shaft 23 resting in the grinder guide extension 24. The direction of the holes in the supports 23 is such that the axis of the plugs 2| is in line with shaft which is to be ground. the plugs 2| passing through thecenter of the shaft 23 is indicated at A-A in Figure 7.

The motor frame has upper and lower tubular extensions 25 and 26 respectively, the upper extension being slidably mounted and guided in the casing 21 which is provided with shoulders or lugs 28. These shoulders are-drilled-in line with the center of the plugs 2| 'to' receive hardened plugs 29 having flat surfaces which rest upon and are supported by the cylindrical outer surface of the plugs 2|. The plugs 29 are also provided with ball shaped extensions 30 engaging the walls of the bores 22 in the plugs 2| so as to prevent any slippage of the casting 21 and motor frame with respect to the support member l6. By this arrangement, a substantial, but limited, rocking of the grinder upon the guide arm is allowed.

The 1113s or shoulders 28 are not in the same plane with the axis frame extensions 25 and 26. The grinder shaft and grinding wheel are concentric with these extensions. The center line of the grinder shaft, when it is in a position parallel to a plane containing the centers of the the center of the The center line of supports 2|, 23 and the center of the shaft 23 is spaced away from said plane by approximately one fourth of the diameter of the average grinding wheel 3| which is intended to be used. This arrangement is for the purpose of giving maximum flexibility of adjustment of the hook member 24 with respect to the guide arm l6.

The diameter of the grinding wheel 3| is preferably of the same length as the diameter of the crank bearing which is tobe'ground. It is contemplated for instance that the operator would select a two inch wheel for grinding a crank" bearing two inches in length and a two and one eighth inch wheel for grinding a bearing two and one eighth inches long. The arrangement of these parts as stated and the cooperation of the plane and curved surfaces of the supporting blocks is more clearly illustrated by the geometrical diagram of Figure 3.

In order to maintain the support bearings 29 in contact with the cylindrical surfaces of the supports 2|, I provide a pair of bolts 32 passing through the guide arm I6 and the shoulders 28. Thebolts 32 areprovidedwith a nut and washer 33 at one end for tightening against the coil spring 34. Thestrengthof the spring 34 is ample to hold the motor firmly in contact against the guide am but not so strong as to prevent the limited rocking movement of the motor with respect to the guide am. It will be understood that some play is allowed in the holes for the bolt 32 and in the spring seat for the spring 34 so that no binding action will occur.- The normal action of the spring 34 would be the cause of rocking of the motor with respect to the guide arm but this as shown in Figure 7. The end of the screw 28 is provided with a socket as shown inFigure ii to receive a ball 81 which is integrally formed with a slide member 38. The motor frame It is provided with guide ways 29 for slidably receiving the member 38 which is guided for vertical-rnovernent therein. By operating the hand wheel 88 the motor can be rocked so as to sweep the end of the grinding wheel ll across the surface ofthe shaftbearing 23. In order to prevent dirt and grit'from' entering between the surfaces inch of adjustment of'the motor l9 and grinding wheel 8|, and in order to maintain this adjustment of the grinding wheel, aset screw 18 is provided to bind against the upper part of the collar flange 11. Thus it will be seen that a minute adiustment of the grinding wheel can be readily accomplished and maintained.

The grinding wheel 8| is driven by means of the shaft 30 rotatably mounted in the lower casing extension 28 and a thrust bearing 8| is provided orrfthe'lower end of the shaft 80 closely adjacent the wheel'il whichlatter together with the telescopic connection 82 at the upper end of this shaft 88 permits aslight inward movement of the wheel 3| and thus eliminates the possibility of fracture d by shock from sudden contact with the surface to and longitudinal adjustment of the grinder guide 24 so that if shafts of different diameters are to be ground, the. grinder guide can be adjusted to such a position that the center of the shaft which is being ground will be concentric with the cylindrical surfaces of the support members 2|. In order to enable the-operator to quickly make the desired adjustments a scale 43 may be provided on the adjacent surfaces of the members It and 24 with graduations indicating the diameter of the bearing corresponding to the adjustment of the two members.

The grinder guide 241s provided with replaceable wear blocks 44 which are pivotally mounted on the pins 45. These wear blocks are formed with four intersecting concave surfaces, the radius of the concave surface being smaller than the radius of the smallest bearing which is likely to be ground. This arrangement provides'for practically a scraping contact between the wear blocks and the hearing which is being ground so as to scrape off dirt from the stone during the rotation of the shaft. The wear blocks can be turned intheir mounted position or completely removed and replaced by removing the plate which is held in position by one or more screws 46.

The tubular extension 25 of the motor casing, which is slidably mounted in the bore of the cast casing 21, contains a tension spring 85 which is rigidly attached to a tubular plug 86 rigidly mounted in the lower end of extension 28 adjacent the motor. The plug 68 is of tubular form and is internally threaded. The other end of the spring 65 is rigidly connected to the bearing member 81 mounted in the sleeve 88 arranged at the upper end of the cast casing 21. The sleeve 68 includes an upper flange which rests upon the upper portion of the cast casing 21, the latter being formed with an inturned flange portion for this purpose. A 1 bolt 88 extends through the flange of the sleeve 68 and the upper inturned flange portion of the cast casing and secures these parts together. Rotatably mounted in the tubular extension 25 and the bore of the cast casing 21 is a shaft 10 provided with screw threads 1| which engage the threads of the plug 68. A hand wheel 12 is fixedly mounted on the shaft 10, and this hand wheel includes the collar 13 provided with graduations 14 in registration with the gauge mark 15 on tubular casing 21. A washer plate 18 is interposed between the upper face of the sleeve 88 and the inturned flange 11 of the collar 13 to complete the assembly. The scale 14 is graduated in such a manner as to read in thousandths of an '75 be ground. The provision of the slip Joint 82 also permits essential movement of the shaft due to changes in temperature which may occur during grinding operation.

To further safeguard the assembly, the motor structure includes the fan element 82 fixed to the motor shaft, within the motor casing or adjacent thereto, whereby during normal grinding operations themotor may be kept properly cooled bythe blasts-therefrom; In instances when the grinder "is operating an'dthe grinding wheel is moved out of contact'with the bearing surface the grinder speed is essentially accelerated and in such instances the fan, because of its structure, tends to retard the racing of the operating parts due to resistance which is rapidly built up as the fan speed is increased.

In the construction shown inFigs. 16 and 17 the grinding operation may be performed without removing the crank shaft from the motor. The crank case of the engine is diagrammatically indicated with reference numeral 85. The crank shaft 6 remains mounted in the crank bearings I l but the connecting rods are removed from the crank bearings l2. The lower half of the crank case having been removed a pair of bracket members 88 are attached to the upper crank case 85 or engine base by means of screws 81 in holes 88. It will be understood that the holes 88 are normally provided in the engine for reception of the bolts which hold the lower half of the crank case in position. The hangers 86 are provided with bearings 88 at their lower ends to receive the countershaft 8! which is rotatable and slidable in the bearings 80. Connecting rods or frame members 82 are rigidly connected to the countershaft Si in parallelism with each other and these members 82 are provided at their free ends with mountings 88 to receive the guide shaft 94. It will be noted that the holes 88 in the conventional engine construction are formed in line parallel with the axis of the crank shaft and that the shafts 8| and 84 will for that reason be maintained in parallelism therewith. The grinder construction 3i, hook 24 and guide arm [6 in Figures l6 and 1'1 are identical with thecorresponding members in the other figures. The member i4 and counterweight, however, are replaced by a similar, though perhaps not identical member I which is pivotally mounted at one end on the shaft 84 while the other end is mounted on the bearings i1. In this arrangement the grinder proper is suspended from the crank shaft and crank bearing i2 by means of the hook or grinder guide 24 so that there is no need of a counterweight to hold the same in contact with the crank bearing.

In operation, the crank shaft is rotated in any suitable manner, preferably by mounting one or both rear wheels of the automobile on a motor thereby rotating the crank shaft. The crank shaft could, of course, be rotated with the usual starting motor, although it would be desirable to provide a separate source of current to prevent undue strain on the storage battery. While the crank shaft is being rotated in this manner, the grinding wheel 3I is gradually fed up against the crank bearing I2 by means of the hand wheel I I. The operator also sweeps the wheel back and forth across the bearing by means of the hand wheel 35. In the present modification, the grinder is oscillated on a pivot, the axis of which extends in a plane parallel to the axis of the grinder and in this manner the grinder may be swung across the bearing at such a tangent as the arrangement of the parts may provide.

With respect to the device shown in Figures 18, 19, 20 and 21, I utilize a different principle of operation for maintaining the cylindrical shape of the bearings which are to be ground. Instead of mounting the grinder on a rocking support, I mount it on a pivot having an axis perpendicular to a plane containing the center of the bearing which is to be ground. The axis of the pivot is parallel but not concentric with the axis of the grinder shaft, so that by swinging the grinder on the pivot, the grinding wheelmay be swept across the bearing surface while maintaining the face of the grinder wheel in the same place.

The mounting of this modified form for grinding operation is illustrated as corresponding to the previous structure and utilizes the standard I3 at the upper part of which is pivoted the walking beam l4, by means of a countershaft or centers [5. The ends of the walking beam I4 are mounted on the opposite end portions of the horizontal pivot pin or rod I00, and are secured thereon by nuts IOI in threaded engagement therewith, threads being formed on the extremities of the pivot pin I for this purpose.

The guide arm l6 of the present form differs materially in structure from guide arm of the pre ferred form in that it includes a hub portion I02 which is mounted on the horizontal pivot pin I00 and is interposed between the extremities of the walking beam I4 thereby providing a neat and compact assembly of these parts. The hub I02 of the guide arm I6 is formed with a fixed vertically extending tubular body or pintle I 03, slightly enlarged in diameter near its lower extremity to provide an annular shoulder I04, and the enlarged portion I defined by the shoulder I04 is extended inwardly forming an offset lower projection I06, the upper face I0'I of which extends in a common plane with the shoulder I04 and is in fact a continuation thereof.

The upper face I01 of the offset portion I06 is drilled vertically at a point in common plane with and interposed between the vertical axis of the tubular extension I 03 and the normal centered position of the vertical axis of the grinder I08, indicated by reference character I09, to provide a socket for the pin H0. The passage through the vertical tubular member I03 is restricted by the thickened wall portion I I I and this restricted passage is threaded throughout its length to receive an adjusting pin II2 carried by the tubular motor casing extension on pintle retainer II4 which is secured to and spaced from the motor casing II5 by connections including a web structure comprising spaced walls I I6 and Ill. The wall H6 is formed with a reenforced portion II8 having central threaded opening II9 for the reception of the threaded shank I20 of the adjusting screw, the inner end of which engages the adjacent face of the pin H0, and the outer end is provided with the handle member I22 of suitable design. The wall I" includes an intermediate portion parallel to that wall portion of wall II6 formed with the threaded opening IIS and this parallel wall portion of wall I I1 is provided with a fixed socket or cup I23 containing a coiled spring I24 and plunger I25, the latter engaging at its outer end the pin I I0 at a point diametrically opposed to that part of the pin engaged by the adjusting screw I2I. Each of the walls 6 and III includes flared outer end portions I26 which are shaped to snugly engage the motor casing H5 and be secured thereto by bolts I21. Horizontal webs I26 and I29 connect the upper and lower marginal edges of the walls I I6 and I I1 and lend the essential rigidity to the assembly.

The upper end of the pintleretainer H4 is flanged at I30 to provide a supporting surface for the cap I3I, which is fixed thereto by screws I32, and on this cap is seated the collar I33 and the hand wheel I34. The cap I3I, collar I33 and hand wheel I34 are formed with central axially aligned bores through which the upper end of the adjusting pin II2 extends. This pin H2 is provided with a shoulder or fixed collar I35 which abuts against the under face of the cap I3l and at a point intermediate the collar I35 and its upper extremity, it is reduced in diameter. to form a shoulder I36 which engages the under face of the collar I33. It will be-noted, that the bore through the collar I33 and hand wheel I34 is reduced to accommodate the reduction in the diameter of the adjusting pin H2 and that a nut I36 is threaded on the end of the pin II2 to function with the lock washer I31 to secure the wheel I34 and collar I33 fixedly together. The collar I33 is formed with an annular seat I 38 in its under face and concentrically of its bore to receive the thrust I bearing assembly I39 which latter facilitates the movement of these parts to provide accurate adjustment in accordance with scale markings I40 formed on the adjacent outer faces of the collar I33 and cap I3I.

Arranged on the pintle I03, and interposed be- 7 tween the shoulder I04 thereof and the loweredge of the retainer H4 is a coiled spring I which cooperates with the parts in facilitating the essential accurate adjustments through movement of the hand wheel I30. This spring also provides the necessary resiliency for operating the structure without injury to the parts.

From the foregoing, it-will be obvious that while the application of the structure to a hearing for grinding is essentially the same, either when the crank shaft is in situ or disassembled, nevertheless the operation involved in the actual grinding differs materially in many respects. In the first instance, the motor and grinding wheel assembly includes a casing to which is secured a tubular body II4 which constitutes a pintle retainer, in that it receives the tubular pintle I03 fixed to the hub I02 of the guide arm I6.

The hinge thus formed by the pintle I03 and i the retainer II4 permits a swinging movement of the motor and grinder assembly, and this movement is subject to'control or regulation by means of the adjusting pin H2 and the adjusting screw I2I. When the guide arm I6 and the grinder guide extension 24 have been adjusted in accordance with the requirements of the crank shaft dimensions by utilization of the graduated joint 43, conventional to all forms of the device.

whereby the grinder guide 24 is properly engaged threaded adjusting screw" iywhich engage opa grinder frame,said support member being parallel to the axis of the crank shaft which is to be ground, said grinder framebeing connected to said support member by pivoted linkage, said linkagehaving the axes of its pivots parallel to .rthexaxisoflthe-crgnk shaftzwhichdsto-be ground, z; said Ira;ne-:.=having;a-'hook constructed and arpos'ed sides of the pin I I0 and control the swinging movementof the grindenwheeltacros's'the guide means for the assembly, is in a plane perpendicular to the axis to be ground.

In Figures 22 and 23, I show a modified form of guide block or support for the bearing which is being ground. In this form, the guide blocks I50 are provided with a leading edge l5l having greater length than'the trailing edge I52 so as to centralize the wear. These guide blocks are rotatably mounted on the screw I53 which is provided with the bearing surface I for that purpose. A second screw I5! is mounted adjacent the screw I53 to engage the yoke I" which is formed integral with" the bearing block. It will be noted that this arrangement provides a limited rocking movement of the bearing block on the screw I53, but does not allow the bearing block to swing clear around. The purpose of this arrangement is to insure the bearing block seating properly on the shaft which is to be ground without any attention from the operator.

The foregoing invention in .its numerous applications and modifications is essentially sub- Ject to changes in details ofmonstmction -arrd "'35 the axis of said pivot being substantially per-- pendicular to said generating element. I v

2. In a crankshaft grinder, a support, a'f'rame connected to said support by pivot means having an axis parallel to the axis of the crank shaft which is to be ground, a hook connected to said frame and adapted to support said frame by engagement with :the surface which is to be ground, a grinding wheel pivotally mounted on said frame, the pivot of said grinding wheel being substantially perpendicular to the axis of the crank shaft, and means for swinging said wheel about said pivot during rotation of the grinding wheel and of said crank shaft.

3. In a crank shaft grinder, a support, a frame connected to said support by pivot means having an axis perpendicular to the axis of the crank shaft which is to be ground, a cup-shaped grinding wheel supported by said frame and having an axis substantially parallel to the axis of .the pivot means, and means for swinging said frame and wheel about said pivot during rotation of said wheel and shaft so as to cause the axis of said wheel to intersect the axis of the surface which is being ground, and to cause said wheel to be swept across the surface which is being ground.

4. In a crank shaft grinder, a support member,

ranged to support said frame from the surface which is to be grourid, whereby saidfframennay follow the motion of -;,a crank? bearing'df :said shaft during its rotation, a;cup grinding wheel carried by said frame, said wheel being mounted on said frame by means of a pivot having an axis substantially perpendicular to the axis of the crank shaft.

5. In a crank shaft grinder, a frame, a grinder, a pivot bearing forming a connection and support between said frame and said grinder, said grinder having a grinding surface adapted to be moved into contact with the work in a plane parallel with the axis of said bearing, spring 'r'neansbetween said frame and said grinder biasins said grinder in the direction of the work.

6. In a crankshaft grinder, a frame, a grinder, a pivot bearing forming a connection and support between said frame and said grinder, said grinder having a grinding surface adapted to be moved into contact with the work in a plane parallel with the axis of said bearing, spring means between said frame and said grinder biasing said brinder in the direction of the work, and a screw threaded adjusting means for limiting the travel of said grinder toward the work under the influence of saidmring. Lin a cran'ishaft grinder, a frame, a grinder, a pivot bearing forming a connection and support between said frame and said grinder, said grinder having a grinding surface adapted to be moved into contact with the work in a direction parallel with the axis of said bearing, spring means between said frame and said grinder biasing said grinder in the direction of the work, a second spring device tending to rotate said grinder about said pivot, and adjusting means for controlling the amount of said rotation under the influence of said last named spring.

' 8. In a crankshaft grinder, a support parallel with the axis of the crankshaft which is to be ground, a grinder frame, pivoted linkage connecting said support and said frame, a hook connected to said frame and constructed and arranged to support said frame from the surface which is to be ground, a grinder pivotally mounted on said frame, said grinder having a cutting surface lying in a plane parallel to the surface which is to be ground, the pivot mountingv of said grinder being perpendicular to said p ane.

9. In a crank shaft grinder, a support parallel with the axis of the crank shaft which is to be ground, a grinder frame, pivoted linkage connecting said support and said frame, a hook connected to said frame and constructed and arranged to support said frame from the surface which is to be ground, a grinder pivotally mounted on. said frame, said grinder having a cutting surface lying in a plane parallel to the surface which is to be ground, the pivot mounting of said grinder being perpendicular to said plane, and means for swinging said grinder about said pivot, whereby said cutting surface may be swept across the surface which is to be ground.

10. A crank shaft grinder comprising a frame, a guide arm connected to said frame, a grinder motor and grinding wheel carried by said frame,

said guide arm having a pair of spaced pivot members having axes parallel to the axis of the surface which is to be ground, and means for moving the axis of said wheel transversely with respect to the axes of said pivot members, and means for moving said wheel along its axis toward said members.

11. A crank shaft grinder comprising a frame,

a guide arm connected to said frame, a grinder motor and grinding wheel carried by said frame. said guide arm having a pair of spaced pivot members having axes parallel to the axis of the surface which is to be ground, resilient means biasing said wheel in a direction parallel to its axis toward saidpivot members, and adjustable means for limiting such movement of the wheel toward said members.

12. In a crank shaft grinder, a guide arm comprising a hook, a pair of pivots mounted on said hook, and bearing shoes mounted on said pivots, said bearing shoes having a concave surface adapted to receive the cylindrical surface of the shaft which is to be ground in mutual guiding relation, and a grinder motor and grinding wheel connected to said guide arm and adapted to be positioned with respect to said cylindrical surface by contact of said bearing shoes therewith.

13. In a crank shaft grinder, a guide arm comprising a hook, a pair of pivots mounted on said hook, and bearing shoes mounted on said pivots, said bearing shoes having concave surfaces adapted to rest on the surface which is to be ground, a grinder motor and grinding wheel connected to said guide arm, said motor and wheel being adapted to be positioned with respect to said surface by contact of said bearing shoes therewith.

14. In a crank shaft grinder, a guide arm comprising a hook, a pair of pivots mounted on said hook, and bearing shoes mounted on said pivots, said bearing shoes having concave surfaces adapted to rest on the surface which is to be ground, said concave surfaces terminating in sharp edges capable of scraping loose grit off the surface which is to be ground, a grinder motor and grinding wheel connected to said guide arm, said motor and wheel being adapted to be positioned with respect to said surface by contact of said bearing shoes therewith.

15. In a crank shaft grinder, a guide arm, a bearing shoe comprising a member having a longitudinally extending pivot receiving opening, a concave bearing surface parallel to the axis of said opening, said bearing surface terminating in a sharp edge which is capable of scraping loose grit off the surface which is to be ground, a grinder motor and grinding wheel connected to said guide arm, said motor and wheel being adapted to be positioned with respect to said surface by contact of said bearing shoes therewith.

16. In a crank shaft grinder, a guide arm, a bearing shoe comprising a member having a longitudinally extending pivot opening therein, the exterior of said member being formed with a plurality of concave bearing surfaces, said surfaces intersecting in a sharp edge, a grinder motor and grinding wheel connected to said guide arm, said motor and wheel being adapted to be positioned with respect to said surface by contact of said bearing shoes therewith.

JOSEPH SUNNEN. 

